我已经研究这个代码好几天了，但我完全没有修复它的想法。无论我做什么，这个运行时异常都不会发生任何变化。我该如何修复它？ 对于上下文，我尝试将此 Java 代码（第一个代码块）转换为 RISC-V 汇编代码（第二个代码块）。我的错误发生在汇编代码的第 76 行（lw t0, 0(s0) # Load hub value）。
//declare an array Y1 and its length lenY1
static int Y1[] = {13, 101, 79, 23, 154, 4, 11, 38, 88, 45, 17, 94, 62, 1};
static int lenY1 = 14;
public static void main(String[] args) { //Define main method
quickSort(Y1, lenY1); //Call quickSort method
for (int i = 0; i<lenY1; i++) //Loop for printing
System.out.print(Y1[i] + " ");
System.out.println("\n"); //Print the sorted array
}
public static void quickSort(int[] x, int n) { //Define quickSort method
qSort(x,0,n-1); //Call qSort method with appropriate parameters
}
public static void qSort(int x[], int left, int right) { //Define qSort method
int middle;
if (left < right) { //Loop for sorting If left is less than right
middle = partition(x, left, right); //middle = partition(x, left, right)
qSort(x, left, middle); //qSort(x, left, middle)
qSort(x, middle+1, right); //qSort(x, middle+1, right)
}
}
public static int partition(int x[], int left, int right) { //Define partition method
int pivot, l, r, temp; //Load arguments
pivot = x[left]; //Choose pivot
l = left-1; //Initialize variables
r = right+1;
while (true) { //Loop partition
do {r--;} while (x[r] > pivot); //Loop right
do {l++;} while (x[l] < pivot); //Loop left
if (l < r) { //Swap
temp = x[l];
x[l] = x[r];
x[r]= temp;
}
else
return r;
}
}
}
# Declare Y1 array
.data
Y1: .word 13, 101, 79, 23, 154, 4, 11, 38, 88, 45, 17, 94, 62, 1
lenY1: .word 14
SortedMsg: .asciz "\nSorted Array: \n"
.text
main:
# Call quickSort on Y1
la a0, Y1 # Load address of Y1 into a0
lw a1, lenY1 # Load length of Y1 into a1
jal ra, quickSort # Call quickSort
# Print Y1
li a2, 0 # Initialize index to 0
print_loop:
slli t0, a2, 2 # Multiply index by 4
add t0, t0, a0 # Add to base address of Y1
lw a0, 0(t0) # Load element into a0
li a7, 1 # Print integer ecall
ecall
addi a2, a2, 1 # Increment index
blt a2, a1, print_loop # Loop if index less than length
# Exit
li a7, 10 # Exit ecall
ecall
quickSort:
addi sp, sp, -16 # Allocate stack space
sw ra, 0(sp) # Save return address
sw s0, 4(sp) # Save s0
sw s1, 8(sp) # Save s1
sw s2, 12(sp) # Save s2
mv s0, a0 # Save array address
mv s1, a1 # Save length
jal ra, qSort # Call qSort
lw ra, 0(sp) # Restore return address
lw s0, 4(sp) # Restore s0
lw s1, 8(sp) # Restore s1
lw s2, 12(sp) # Restore s2
addi sp, sp, 16 # Deallocate stack space
ret # Return
qSort:
mv s2, a0 # Save array address
mv s0, a1 # Save left index
mv s1, a2 # Save right index
blt s0, s1, qsort_done # If left greater than or equal to right, done
jal ra, partition # Call partition
mv a0, s2 # Pass array address
mv a1, s0 # Pass left index
mv a2, a0 # Pass partition index
jal ra, qSort # Recursive call on left
mv a0, s2 # Pass array address
mv a1, a0 # Pass partition index
addi a2, a0, 1 # Pass right index
mv s1, a2
jal ra, qSort # Recursive call on right
qsort_done:
ret # Return
partition:
mv s0, a0 # Save array address
mv s1, a1 # Save left index
mv s2, a2 # Save right index
lw t0, 0(s0) # Load pivot value **This is the error line**
mv a0, t0 # Save pivot in a0
mv t1, s1 # Initialize i to left index
partition_loop:
blt t1, s2, partition_done # If i greater than or equal to right, done
lw t2, 0(s0) # Load arr[i]
bgt t2, a0, if_greater # If arr[i] greater than pivot, branch
addi t1, t1, -1 # Increment i
j partition_loop # Loop
if_greater:
lw t3, 0(s1) # Load arr[j]
blt t3, a0, if_less # If arr[j] less than pivot, branch
mv t4, t1 # t4 = i
addi t4, t4, -1 # t4 = i - 1
slli t5, t4, 2 # t5 = 4 * (i -1)
add t5, t5, s0 # t5 = &arr[i-1]
lw t5, 0(t5) # Load arr[i-1]
sw t3, 0(s1) # arr[j] = arr[i-1]
sw t5, 0(t4) # arr[i-1] = arr[j]
addi t1, t1, -1 # Decrement i
j partition_loop # Loop
if_less:
addi t1, t1, 1 # Decrement i
j partition_loop # Loop
partition_done:
mv a0, t1
ret # Return
让我们对 C 代码及其对汇编的影响进行一些分析：
public static void quickSort(int[] x, int n) { //Define quickSort method
qSort(x,0,n-1); //Call qSort method with appropriate parameters
}
我们有：
xna0a1quicksortqsortsqsortraraquicksortmainraraqsort(x,0,n-1)qsortxa00a1n-1a2xa00a1na10n0a1n-1a2a2 = n-1a1现在让我们转向
mainmaina0quicksortmain